Method of printing textile material



UNITED STATES its iieierece PATENT OFFiCE BETHOD OF PRINTING TEXTILE MATERIAL No Drawing. Application May 16, 1936, Serial No. 80,218

10 Claims.

My invention relates to improvements in printing textile fabrics.

In the intaglio printing of dyed fabrics where the dye is to be discharged from the fabric by transferring the discharge paste from the engraved intaglio grooves of a printing roller to the fabric, a doctor blade isprovided to normally butter or wipe the discharge paste into the intaglio grooves of the printing roller and this tends to leave a continuous peripheral film of discharge material around the printing roller. This film which is left on the printing roller, which is one of the causes of imperfect printing, is always present due to the practical impossibility of grinding the edge of a doctor blade true to conform to the ground peripheral surface of a print ing roller. As the fabric passes through the machine, this film becomes transferred to the fabric passing through in the form of a light film of discharge material. The ground shade is applied to the fabric in a preliminary dyeing operation, either in the yarn or in the piece and vat or other dyestuffs which can be discharged may be conveniently employed to dye the ground. The fabric thus dyed with a ground is then printed with the discharge paste to either (1) provide a White printed figure, or (2) provide a figure printed with a dye to provide a different printed shade. In either event, it is necessary to discharge the dyestuff in the ground from the printed area by a suitable discharge agent in the printing or discharge paste to remove the ground from the desired pattern-forming area when the dyestuff in the ground and/or printing paste is reduced to soluble leuco form by the action of steam in the ager in the portions of the fabric printed with the discharge material. This film of discharge material likewise tends to slightly reduce or discharge the unprinted dyed area in streaks or all over the fabric and so thus tends to either dull the desired shade of the fabric ground or cause streaks in the fabric ground after ageing. The reducing or discharging agent in a discharge paste comprises hydrosulphite or sodium sulph-f oxylate of formaldehyde or any other suitable reducing agent and by the action of the doctor blade aforesaid, despite the utmost care in printing, a film or streaks of this material are often produced over the surface of the discharged fabric, commonly known as facing. When aged, the hydrosulphite or other reducing or discharging agent employed discharges the dyestuff in the ground along this film or in streaks in addition to in the printed discharge figures and tends to leave in the fabric, white or colored facing streaks sO-called Where this film or streaks of discharging agent has caused the dyestuff in the ground of the fabric to be removed. These socalled facing streaks are extremely hard to avoid. It has been suggested to apply a film of a mild oxidizing reagent to the surface of the fabric after printing to cause this mild oxidizing agent upon the action of the steam thereon in the ager toimmediately counteract and remove the facing film or streaks of the discharging agent, and it has been common in the art to run the fabric between two rollers for this purpose either by again running it through the printing machine or by applying it in a two or three roll mangle, in either instance, by means of a pressure nip which has tended to put the, mild counteracting oxidizing reagent on too thick and to squeeze the mild counteracting oxidizing reagent into the printed areas of discharging reagent to cause corresponding dilution and inefficiency of. the discharging reagent in its printed spots and further tending to press it into the dyed fabric and often causing on ageing an undesirable paleing of the dyed or printed ground.

I have discovered that if instead of applying this film of mild oxidizing reagent by means of nip rolls it be lightly sprayed on the surface of the fabric before or after printing that there will be sufficient mild oxidizing reagent .applied to the surface of the fabric only to counteract any previously formed or later to be formed film of discharging reagent, and that when aged, the light sprays of mild oxidizing reagent on the outer surface of the fabric will quickly and, readily function to cause early dissipation of the facing film of discharging reagent within the ager, to effectively eliminate facing streaks and marks. This film of mild oxidizing reagent may be sprayed on to the fabric either before printing, after printing and drying or within the ager or as a separate operation, in Which case it Wouldbe necessary to dry the oxidizing reagent soon afterwards, but is preferably sprayed on the fabric after printing and drying and immediately prior to ageing.

An object of my invention therefore, is to provide a novel method for overcoming or counteracting the formation of facing streaks caused by roller printing machines, and thus preventing or eliminating their appearance in the finished fabric.

I have attained best results if the mild oxidizing reagent be sprayed on in the form of a liquid solution or emulsion.

I am aware that in the prior art various people TREATMENT (it CHEMICAL FiiODIFI- have suggested the addition of moisture within the ageing chamber to speed the ageing reaction. Deltex Patent No. 1,663,843 shows the application of moisture applied in the form of liquid within the ageing chamber at intervals throughout the ageing reaction and it claims to cut down the excess heat of the reduction reaction. Masland in Patent No. 1,907,429 has shown the idea of spraying within the ager to provide a supersaturated atmosphere within the ager to cause the condensation of water in minute globules on the fabric being aged to keep the reaction temperature down and to provide a vehicle for the more rapid conductivity of heat to the reacting zone. This entails the use of a relatively larger amount of water within the ager to prevent its being dissipated by the temperature of the reaction and the super-heated steam prior to its getting anywhere near the reacting zone upon the fabric and does not necessarily, provide an insurance that moisture from a super-saturated atmosphere is continuously applied to the reacting zone on the fabric. In the prior art patents, the supposition is made thatsome water travels to the reaction zone, whereas it is impossible to know by sight or measurement exactly what conditions or reactions take place in the ager and the desirability of having Water at this point implied. By spraying a liquid solution or emulsion in desired quantity on'the printed or discharged fabric immediately prior to ageing, I am enabled to insure that at the exact zone of reaction between the steam and reducing or discharging or printing agent and dyestuff that (l) the reaction temperature is kept down for optimum conditions, (2) a vehicle is provided at the reaction zone for the more rapid conductivity of heat thereto (it being well known that water is a better conductor of heat than water Vapor) and (3) provide 'a liquid absorption vehicle already on the fabric for the soluble leuco dyestuff as formed without the necessity of employing so much water as where the spray is employed within the ager to apply water vapor for the same general purposes to the fabric. By spraying immediately prior to ageing or in tandem with the ager, the right amount of water is continuously provided at the right spot, namely the actual reaction zone, for the more efiicient and positive achievement of the three results mentioned above.

A further object of my invention therefore, is to provide an improved method of speeding the ageing reaction by spraying the fabric preferably after printing and drying with a liquid solution or emulsion immediately prior to passing it through the ageing chamber regardless of whether a mild oxidizing reagent be contained in the solution or emulsion for the purpose of avoiding facing marks in discharge printing hitherto described.

It is obvious, however, that if the proper amount of a suitable oxidizing reagent for this purpose be incorporated in the liquid solution or emulsion sprayed on to the fabric immediately prior to passing it through the ageing chamber that the liquid solution or emulsion of mild oxidizing reagent in addition to speeding the ageing reaction as hitherto explained will additionally function to oxidize and dissipate the facing film of reducing discharging agent over the ground of the fabric to prevent the formation of discharge facing streaks over the ground in the ageing chamber. Thus, while the moisture adding feature to speed the ageing reaction is most efficient- UESS fiidfilfi A ON F TEXTILES & FlBERS, 2,112,132

oxidizing reagent may be most efficiently applied in solution or emulsion thereof at this same point for optimum effect.

While any suitable mild oxidizing reagent may be sprayed on the fabric to avoid facing marks, I have attained best results by employing A; of 1% to 4% of hydrogen peroxide by weight or of 1% to 3% of Sitol (sodium benzylsulfanilate) by weight for this purpose in water solution, the amount of mild oxidizing reagent employed depending on the nature of the vat or other dyestuffs in the ground and fabrics employed. The amount of liquid solution or emulsion sprayed thereon for speeding the ageing reaction also depends on the nature of said dyestufis and fabric.

Any suitable type of a spray atomizer preferably in the form of a row or rows of jets arranged transversely of the fabric may be employed and the jets are preferably mounted to spray on the fabric from beneath in order to prevent condensation drops from dropping on the fabric. I have found out in actual practice that by employing my method, facing marks can'be more uniformly avoided than by any prior known process at a substantially negligible cost substantially eliminating any rehandling charge such as was formerly thought necessary in applying the mild oxidizing reagent through a supplemental nip either of (1) a mangle or (2) a printing roller, and I have also found out that if a liquid solution or emulsion be sprayed upon the fabric immediately prior to ageing that the average ageing time was reduced between 30 to 40%.

Most printing machines have attachments for drying the printed discharge or dye paste on the fabric immediately after printing and while to achieve best results for the facing prevention feature of my invention, I preferably employ a fabric in which the printed material is thoroughly dried thereon, insofar as either aspect of my invention is concerned and particularly the ageing speeding feature thereof, while a thoroughly dried fabric is preferable, it is not absolutely essential so long as the wet printed portions are prevented from smearing on the other portions.

Throughout the specification and in the claims I employ the word mild when employed with the oxidizing reagent as signifying such an oxidizing reagent as will have substantially no deleterious effect upon the cloth, regardless of the strength or acidity of the solution or emulsion in which it be employed, as it is apparent that the strength or acidity of the oxidizing reagent employed will depend in each instance on the nature and chemical composition of the reagent selected.

It is understood that my invention is not limited to the specific methods described. and that various deviations may be made therefrom without departing from the spirit and scope of the appended claims.

What I claim is:

1. The method of treating dyed fabric when printed with a discharge in a roller printing machine to avoid facing marks in the finished fabric which comprises spraying the fabric with a liquid solution or emulsion of a mild oxidizing reagent.

2. The method of treating dyed fabric when printed with a discharge in a roller printing machine to avoid facing marks in the finished fabric which comprises spraying the fabric with a liquid solution or emulsion of hydrogen peroxide.

3. The method of treating dyed fabric when printed with a discharge in a roller printing machine to avoid facing marks in the finished fabric fears-t list which comprises spraying the fabric with a liquid solution or emulsion of sodium benzylsulfanilate.

'4. The method of treating dyed fabric when printed with a discharge in a roller printing machine to avoid facing marks in the finished fabric which comprises spraying the fabric before printing with a liquid solution or emulsion of a mild oxidizing reagent.

5. The method of treating dyed fabric printed with a discharge in a roller printing machine to avoid facing marks in the finished fabric which comprises spraying the fabric after printing and drying with a liquid solution or emulsion of' a mild oxidizing reagent.

6. The method of ageing fabrics printed in a roller printing machine which comprises-lightly spraying the fabric after printing and drying with water and immediately passing the fabric a through an aging chamber while subjecting it to the ageing action of steam therein.

'7. The method of ageing dyed fabric printed with a discharge in a roller printing machine to avoid facing marks in the finished fabric and to speed the ageing reaction which comprises light- 1y spraying the fabric after printing and drying with a liquid solution or emulsion of a mild oxidizing reagent and immediately'passing the fabric through an ageing chamber while subjecting it to the ageing action of steam therein.

8. The method of ageing dyed fabric printed with a discharge in a roller printing machine to avoid facing marks in the finished fabric and to speed the ageing reaction which comprises lightly spraying the fabric after printing and drying with an aqueous solution or emulsion of a mild oxidizing reagent and immediately passing the fabric through an ageing chamber while subjecting it to the ageing action of steam therein.

9. The method of ageing dyed fabric printed with a discharge in a roller printing machine to avoid facing marks in the finished fabric and to speed the ageing reaction which comprises lightly spraying the fabric after printing and drying with a liquid solution or emulsion of hydrogen peroxide and immediately passing the fabric through an ageing chamber while subjecting it to the ageing action of steam therein. 7

10. The method of ageing dyed fabric printed with a discharge in a roller printing machine to avoid facing marks in the finished fabric and to speed the ageing reaction which comprises lightly spraying the fabric after printing and drying with a liquid solution or emulsion of sodium benzylsulfanilate.

GEORGE E. BENNETT. 

